jd 40c runs bad

mdalton · Jul 9, 2014

after 10-15 minutes, my jd 40c crawler starts to misfire and runs badly. i have to pull the choke and it runs better for a while. then i push in the choke after it misfires again. i rebuilt the carb, cleaned plugs, fuel lines and gas tank. also installed new voltage regulator. what is the problem?

mab570diesel · Jul 10, 2014

sure sounds like a fuel issue if it runs better when you pull the choke out.

Bret4207 · Jul 10, 2014

If pulling on the choke makes it smooth out then it surely a fuel issue. Have you tried opening the main jet a little instead of choking it? Sometimes a warm engine needs a little richer mix for some reason. Otherwise, go back through the fuel system, probably dirt someplace.

Anonymous-0 · Jul 11, 2014

Also check your throttle butterfly shaft. It should be snug and have a (felt?) seal. If it leaks air it will lean the mixture.

Donald Lehman · Jul 12, 2014

First off don't waste your time cleaning plugs. put a new set in and see what happens. These days, fouled plugs very seldom work properly after cleaning. Did you have the coil tested? A bad coil has a habit of working fine until they get heated up. Unhook your fuel line from the carb and let it run into a bucket for 5-10 minutes. If the flow slows down after time, you have a bunch of crud in the fuel tank that is plugging the line as it accumulates. When you cleaned the carb and fuel lines, did you have a lot of crud in them? If so clean the fuel tank. If not get that coil checked out.

jd 40c runs bad

mdalton

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mab570diesel

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Bret4207

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Anonymous-0

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Donald Lehman

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